Solid state relays


Thread Starter

Colin Cooke

I happened upon this site with a web ferret. I saw this description: Solid state relays - control input 4-20 milliamps. This is just what I am looking for, but now can't find any reference to the same. Can anybody help. Many Thanks Colin Cooke

Steve Myres, PE

If you want a 4-20ma input, you're probably looking for analog power control, for a larger AC power load, I will assume. I have used Crydom PCV series relays with good results. These relays look just like a standard on/off hockey puck type SSR, but they accept a 2-10VDC input signal and phase switch a substantial AC load (I use one for 20A at 240VAC). If you wire your 4-20 signal to the input with a 500ohm resistor shunted across the input terminals, this will translate into a 2-10VDC signal at the relay input. You can review the specs at: Steve Myres, PE [email protected]